Electrodepostion of Gold-Based Multilayer Systems

Gold 2003

Milko Monev, Alexander Pfund,

Abstract
To meet the increasing demands of the quality and long term stability of technical systems also the applied materials have to full fill higher standards. This is of special importance where the function of a whole system depends on the reliability of the used materials for example for connector systems in automotive, computer and other electronic equipment’s.

In most cases for connector systems electro deposited top layers are applied. To improve the quality of the applied layers new electro deposited systems are developed. One important field of research are the development of composit materials as dispersion coatings and multilayer systems. Multilayers are systems with a high number of single inter-layers of different metals or alloys with the wide chance of the alloy composition.

As gold is one of the most important contact material for high quality connector systems it is used as basis for the development of multilayer systems. For the electro deposition of multilayers two different methods can be applied, the single and the dual plating process. As in the dual plating process two different electrolytes are used, the single plating process allows the formation of multilayers from one electrolyte. In the presented research results cobalt, iron and nickel are used besides gold for the formation of the multilayers. The properties of the layers can be influenced in a wide range by the change of electrolyte composition and the process parameters as current density, current waveform, temperature, hydro-dynamic conditions at the electrode surface and by the number and thickness of the inter layers of the deposited materials.

In the presentation the fundamentals of the electro deposition of multilayer systems are described. For the investigation of the properties of the multilayers different techniques are applied. One of the most important parameter are the thickness of the total layer and of the applied interlayers. The thickness of the inter-layers can be varied between a few manometers up to micrometers. The wear resistance, the hardness, the plug-in forces and for special systems also the bondability are measured as this parameters are important for the technical application of such layers.

For the description of the structure composition and surface properties the sample where also investigated by scanning electron microscopy (SEM), energy dispersive x-ray-analyses (EDX) and glow discharge optical spectroscopy (GDOS).

The presentation show’s that the deposition of gold based multilayers is possible and that the properties of such systems can be varied in a wide range what opens new fields of applications of such materials.